Apparatus and method for filling gas storage cylinders



Nov. 21, 1950 HITTL 2,530,523

APPARATUS AND METHOD FOR FILLING cAs STORAGE CYLINDERS Filed March 2, 1944 s Sheets-Sheet 1 INVENTOR ANTON E. HITTL 4% T ATTORNEY Nov. 21, 1950 A. E. HlTTL 2,530,523

APPARATUS AND METHOD FOR FILLING GAS STORAGE CYLINDERS Filed March 2, 1944 3 Sheets-Sheet 2 SW 55'54PRV y 1 {1 m 5\ M a m 25 I AU7UMAT/C CHARGING EQUIPMENT CYCLE TOPP/NG OFF WITH FALLING PRESSURE RAP/D FILL ING "EQUAL/ZAT/ON +CLOSING CYL/NDER VALVES -BLOWDOWN --CHANG/NG CYLINDERS PRESSURE VARIATION /N THE CYLINDERS ON EACH RACK O 40 80 I20 I60 200 240 280 320 360 400 440 480 520 TIME IN SECONDS lNvENToR ANTON 5mm 4139.4. BY

ATTORNEY Nov. 21, 1950 A, E HITTL 2,530,523

APPARATUS AND METHOD FOR FILLING GAS STORAGE CYLINDERS Filed March 2, 1944 3 Sheets-Sheet 3 F/LL/NG EVACUAT/NG IZAT/ON DOWN INVENTOR ANTON E. HITTL ATTORNEY Patented Nov. 21 1950 UNITED STATES PATENT OFFICE APPARATUS AND METHOD FOR FILLING GAS STORAGE CYLINDERS Anton E. Hittl, Buffalo, N. Y., assig'nor to The Linde Air.Products Company, a corporation of Ohio Application March 2, 1944, Serial N 0. 524,740

Claims.

method disclosed in such application involves a topping ofi operation with a slowly rising cylinder pressure, and the mechanism disclosed in such application is spring-operated. Such method is, therefore, subject to certain disadvantages. For example, topping ofi with a rising pressure requires the use of a high pressure electric shutofi valve for the equalizing line, and a back pressure valve in the charging line, both of which are expensive and difiicult to maintain in satisfactory operating condition. Furthermore, such spring-operated mechanism requires an appreciable amount of manual labor to cook the spring.

Therefore, the main objects of the invention are to provide an improved topping-01f cycle and a power-operated mechanism for overcoming undesirable features of Smiths four-rack two-cylinder system; and to provide a light and compact cylinder filling system which is capable of charging cylinders in pairs at a rapid rate of the order of 25,000 cu. ft. per hr., for example.

In general, these objects are accomplished by a novel power-operated mechanism comprising a piston driven by compressed air for operating the control valves, and performing the topping-ofi operation with a slowly falling cylinder pressure.

In the four-rack two-cylinder system the general operating procedure is such that the cylinders are filled in pairs, there being stations for two pairs of cylinders on either side of the device. The charging is done in such a manner that an operator works progressively around the device. The manual operations consists of (a) closing two cylinder valves immediately after a signal light flashes; (b) turning an operating 'handle through 90 degrees so that the handle is over the cylinder valves next to be closed; and (c) disconnecting filled cylinders from the rack and replacing them with empty cylinders. The operator then steps to the next pair of cylinders, in a clockwise direction, and upon a signal from the light repeats such operations. According to the present invention, when filling the customary or standard size of oxygen cylinders, for example,

the cylinders are evacuated, filled, topped 01?, and then removed from the rack. The rapid filling of the cylinders is accomplished at a constant rate which is such that about cylinders per hour can be filled. As soon as one group of cylinders has been rapidly filled to a predetermined pressure, the filling of another group is started.

Since the filling can be accomplished in about one-half the time required for evacuation, two

pairs of cylinders are filled while one pair is being evacuated. While one pair of cylinders is being rapidly filled, a second pair is completing its final period of evacuation, a third pair is completing its initial period of evacuation, and the fourth pair is being slowly bled down or topped off and replaced by empty cylinders.

According to this invention the cylinders are slightly overcharged and the topping off is then accomplished by slowly bleeding gas out of the overcharged cylinders back into the filling line.

' In this case, control of the filling pressure is done with a slowly dropping cylinder pressure. This relatively slow rate of flow reduces the errors caused by varying time lags in the valve-operating mechanism and also reduces the difierence in final cylinder pressures resulting from variation in the pressure drop through the cylinder Valves at high rates of flow.

The apparatus is light in weight and compact for mounting on a mobile pumping unit which also carries the gas material, such as oxygen in the liquid phase, and the cylinder evacuating and f liquid pumping and vaporizing equipment, al-

though the invention is not limited to portable Fig. 4 is a graphical representation of the timing operations involved in filling pairs of gas storage cylinders according to the invention; and

Fig. 5 is an elevational view of a control system adapted to operate the valves in the proper sequence.

Referring to Fig. 2, eight gas storage cylinders l9, each equipped with a valve fitting it, are arranged in four pairs. nected to cylinder racks or manifolds A, B, C, and D. Each cylinder rack or manifold is provided with a frangible disc safety device 13, and a pressure gauge 24. The four manifolds are connect- Such cylinders are con-- ed to four separate pipe lines or headers, to wit: an evacuation header l5, an equalization header 59, a filling header M, and a blow down header 8!.

The evacuation header I5 is connected to a suction or vacuum pump, not shown, and separated from it, if desired, by a valve 3!]. The header also contains a safety device It, and the connections between such header and the several manifolds contain evacuating valves Tl.

The equalization header 59 is connected to the several cylinder manifolds or racks through equalization valves 66. The header 59 is also connected to a gas supply line 54 through parallel branches consisting of a continuously open two-way bleed line 6!], and a by-pass line containing a reverse flow check valve 68. Header 59 also is connected to a gas pressure gauge 68 comprising a mercury column which is fitted with spaced contacts 59 and "it, Fig. 3, to control the operation of the electrical circuit.

Filling header 64 is connected to the several manifolds through filling valves 65. Such header B4 is also connected to the gas supply line 54.

Blow down header 8| is open to the atmosphere at one end, and is connected to the four manifolds through blow down valves 45. Such header 8| also is connected to the gas supply line 54 through a safety device valve RV. The valve RV is electrically operated by a solenoid L2 actuated by current supplied to leads U.

The gas supply line 54 is connected to the headers 85, 84, and 59, as mentioned above, and contains a high pressure safety device 51, a high pressure gauge 58 provided with electrical contacts, and a gas accumulator 55, the accumulator connection being provided with a valve 56.

The several valves associated with the four cylinder racks are controlled by a pneumatic motor arrangement as shown in Fig. l. A compressed air supply line W is connected to any suitable source of supply through a manually operable valve V. The line W is provided with an adjustable air pressure regulator X which is preferably set at a predetermined value. An air. pressure operated switch T, which is adapted. to be closed when the air pressure is above a certain value, is preferably set to operate at a pressure which is less than that at which the regulator X is set. A pneumatic motor ML is automatically controlled by a four-way solenoid operated air valve mechanism. Such mechanism comprises a lever Y which is pivoted at Z and has a tension spring E connected to one arm, and an armature F of solenoid L1 connected to the other arm. The first arm is connected to air inlet and exhaust valves EI and EE, while the other arm is connected to air inlet and exhaust valves FI and FE. Those valves are connected through suitable piping means to the air supply line W, to opposite ends of the cylinder L, and to the atmosphere through an exhaust pipe WE. The arrangement is such that energization or de-energization of the solenoid L1 results in a one stroke movement of a gear rack N, forward or backward. When the gear rack N makes a single stroke, both gears O and R are turned slightly more than one quarter turn.

The electrical control system, Fig. 3, comprises several parallel circuits through which current can flow from a power source, such as a battery 5|, when a switch MS is closed and a safety fuse 83 is in the circuit. When the mercury 82 in the gas pressure gauge 68 reaches the lower contact 69, the circuit is not completed because switches AR1 and ARz are open. At higher gas pressures, contact 18 is reached by the mercury and a circuit is established through relay R1. This closes switch ARi and opens switch BR1. The closing of switch AR1 energizes the relay R2 through the low pressure contact 69 of pressure gauge 58 which is still in contact with th mercury. Energization of the relay R2 closes switch AR2 and energizes a heavy duty relay R4. The subsequent closing of switch AR4 energizes solenoid L1 controlling the air valves FE, FI and EE and E1 to the air motor cylinder L and piston M, thereby operating the gear rack N one stroke. Energization of the relay R2 also closes switch BB2 and opens switch CR2. As a result the relay R3 is energized and switches ARs and BB3 are closed.

When the gas pressure drops, contact 19 is broken and relay R1 is de-energized. This opens switch ARi but relay R2 remains energized through switch AR2. As the lower contact 69 is broken, relay R2 is de-energized. This opens switch AR2, de-energizing the relay R4, and opening switch ARi. The solenoid L1 is then de-energized, causing the air valves FE, FI and EE and E1 to be operated so that piston M returns to its original position. The de-energization of relay R2 also opens switch BB2 and closes switch CR2. The closing switch CR2 completes a signal light circuit through switch Hits, a signal light rotary switch member 869, a stationary switch member SA, and a signal light 25.

The circuit containing the switch BB1 also contains a manually operated switch MU; a manually operated stop switch SS in parallel with the switch BR1; the switch '1 which is pressure actuated from the air supply line W; the pressure switch PS actuated from the gas supply line 54; and the solenoid coil L2 which operates a quick release valve RV in the blow down header 8 l The'valves 45, 65, i1 and 66 (Fig. 2) are operated by the piston M of the air motor acting through gear rack N and pinion gears R and 0. Gear R operates the equalization valves 68 and gear 0 operates the filling and evacuation valves 65 and i! (Fig. 5). When gear rack N is moved forward, gear R; is turned counter -clockwise when seen from above. Gear R is loose on. a shaft it so that the gear R slips under a clutch J without alfecting the position of the shaft 29, a ratchet K preventing any rotation of the shaft in the direction of rotation of gear R. When rack N is moved to. the rear, gear R is turned clockwise, and clutch J causes the shaft. 29 to rotate with gear R, the. ratchet K permitting operation in such direction. Rotation of shaft 28 causes rotation of an equalization valve stem 36. The valve stem 36 operates a separate set of equalization valves 66 for each quarter turn of the valve stem. The valve stem 35 is turned one quarter revolution each time the gear rack N is moved to the rear and the valve stem does not turn when the rack N moves forward. In'the same manner, and by virtue of a similar but reversed ratchet J (on the left of Fig. 5) and meshing gears 39 and 48 on filling and evacuating valve stems 3'! and 4|, respectively, the latter are actuated through one'quarter turn each time the gear rack N moves forward, and such valve stems are stationary on the reverse movement of the gear rack N. As in the case of the valve stem 36, valve stems 31 and 4! operate 71 each quarter turn of the valve stems.

Operation of the equipment is described below en the basis of the cylinder racks being filled with cylinders and the charging operation being in progress. Under these conditions one rack would be filling, one rack would be at the final stages of evacuation, one rack would be at the early stages of evacuation, and one rack would be at equalization. These conditions are shown graphically in Fig. 4. With the passage of time, the charging, evacuation, and equalization processes progress toward completion. Equalization is completed earliest, and when equalization is complete, as indicated by the opening of contact 69, Fig. 3, the automatic valve operation controlled by air motor ML is initiated. Valves FE, FI and EE, EI, are operated so that piston M and gear rack N are moved to the rear, Fig. 5, operating equalization valve stem 36. This closes equalization valve 66 of that rack where equalization is complete and opens it to that rack which is filling.

The operator then closes the valves 18 in the equalized cylinders, operates the blow down valves 45 by turning handle l9? and shaft 43, then removes such cylinders from the rack, and replaces the cylinders with empty cylinders ready for charging. Shortly after the change of cylinders has been efiected, the gas pressure in the rack which was being filled has reached the point where the contact '10, Fig. 3, is made. This closes switch ABA and energizes solenoid L1, so that valves FE, FI, and EE, EI are reversed and piston M and rack N are moved forward, Figs. 1 and 5, operating filling and evacuating valve stems 31 and 4 I. This valve stem operation closes the filling valve 65, Fig. 2, to that particular rack, closes the evacuation valve T1 in the rack next to be filled, opens the filling valve 65 in that rack and opens the evacuation valve 17 to the rack on which empty cylinders have just been installed. The rack which had been filling is overfilled somewhat at the time of valve change occasioned by closing contact 19, Fig. 3, and this excess gas pressure bleeds down by flow of gas through the bleed line 66, Fig. 2, the gas pressure in line 54 being reduced because of the rapid flow of gas into the cylinders just starting the actual charging procedure. When sufiicient gas has blown through the line 66 to cause the contact 69, Fig. 3, to open, the automatic valve system is again placed in operation as outlined above.

When equalization is completed at any rack, as indicated by opening of contact 69, Fig. 3, a light 25 will glow to indicate this fact to the operator. After closing the cylinder valves, the blow down valve $5 is operated to release the pressure in the manifold. At the same time switch SE is opened momentarily to de-energize relay R3 which opens contacts AR:; and BB3. Also. at about the same time the rotary switch member I99 is operated one quarter turn to contact selectively the next stationary switch member of the series SA, SB, SC, SD. All these latter functions are coordinated to a single control point (handle lill) such that when the blow down valve 45 is operated by a one quarter turn of stem 43, Fig. 6, by manual operation of handle I01, the switch SE, Fig. 3, is opened momentarily (the rotary switch member I09 being on the stem 43) and the proper switch member of the group SA, SB, SC, SD is selected and contacted. The light and the position of the handle l8! point to that rack which is next to be changed, as shown in Fig. 1 of Smith 2,411,235.

In operation then, the operator takes his place in front of the rack toward which the handle I01 points, and when a light glows he first closes" the valves IS on the individual cylinders 19, and

then, with a single quarter turn of handle lil'l, operates the blow down valve 45, interrupts the circuit to stop the light from glowing, and sets the switches so that a light will show when equalization is complete at the next rack. He then disconnects the cylinders 19 and connects in their place other cylinders to be evacuated. He then moves to the next rack, the one toward which handle 10"! is pointing and repeats the process after the corresponding signal light 25-is illuminated.

What is claimed is:

1. In a multiple rack gas storage cylinder filling apparatus of the class set forth including cylinder evacuation, filling and equalization lines, together with a plurality of cylinder racks each connected to such lines by corresponding individual evacuation, filling and equalization valves, the combination with automatic means responsive to the gas pressure in such equalization line, which simultaneously opens the evacuation valve of one rack to which an empty cylinder is connected, opens the filling valve of a rack to which an evacuated cylinder is connected, and closes the filling valve of a rack to which a filled cylinder is connected, when such filled cylinder becomes overfilled, whereby the resulting rush of gas into such evacuated cylinder reduces the pressure in said filling line to a Value below that of said overfilled cylinder, of a bleed line providing continuously open two-way communication between said filling line and said equalization line, through which excess gas flows from such overfilled cylinder back into the filling line until the pressure in the overfilled cylinder falls to the desired value, whereupon said pressure responsive means simultaneously closes the equalization valve in the rack to which such filled cylinder is connected, and opens the equalization valve in the rack to which the cylinder being filled is connected. v

2. In a multiple rack gas storage cylinder filling apparatus, as defined by claim 1, a reverse fiow check valve in parallel with said bleed line, which automatically closes when gas is bleeding from the overfilled cylinder, and opens when the equalization valve in the rack of the cylinder being filled is opened, resulting in the flow of filling gas through the equalization valve as well as through the filling valve.

3. In a four-rack multiple gas storage cylinder filling system of the class set forth which comprises a cylinder evacuation line, a cylinder filling line, a cylinder equalization line, and a rack blowdown line, and corresponding valves connecting each cylinder rack to said lines, the combination with a continuously open two-way bleed line connecting said filling line and said equalization line, of automatic means responsive to gas pressure in said equalization line when a predetermined excess gas cylinder pressure is reached for simultaneously opening the evacuation valve of the rack to which empty cylinders are connected, closing the filling valve of the rack to which overfilled cylinders are connected, and opening the filling valve of the rack to which evacuated cylinders are connected, whereby ex cess gas in the overfilled cylinders flows back through said bleed line into the filling line due to'the reduced pressure therein caused by the rush of gas into the evacuated cylinders, said means being also responsive to a predetermined lower pressure for simultaneously closing the assaszs 7 equalization valve of suchra'ck to which the filled cylinders are connected, and opening the equalization valve of such rack to which the cylinders being filled are connected, when the pressure in the filled cylinders falls to the desired value.

4. In apparatus of the class described for filling gas storage cylinders comprising the combination with cylinder evacuation, filling and equalization lines, a plurality of cylinder racks each connected to said lines by corresponding cylinder evacuation, filling and equalization valves, a continuously open two-way bleed line connecting said filling and equalization lines, and an automatic mechanism comprising means mechanically connecting said evacuation filling and equalization valves for sequential operation when such means are actuated, common means adapted to actuate such means, a motor connected to drive said common means, a control circuit operatively associated with said motor, gas pressure responsive means in communication with said equalization line which energizes said control circuit in response to a predetermined gas pressure which is above the desired final cylinder gas pressure, resulting in the sequential operation of said filling, equalization and evacuation valves, whereby the filling valve to the overfilled cylinder is closed, the filling valve to an evacuated cylinder is opened, and the evacuating valve to an empty cylinder is opened, the resulting rush of gas into the evacuated cylinder reducing the pressure in the filling line to such an extent that excess gas from the overfilled cylinder flows back 3 through said bleed line and reduces the pressure of the overfilled cylinder, resulting in the operation of said pressure responsive theme, and closure of said equalization valve to the filled cylinder and opening of the equalization valve to the cylinder being filled, when the overfilled cyl inder pressure falls to the desired value.

5. In the art of first evacuating and then rapidly filling gas storage cylinders with gas under pressure, the improvement which comprises rapidly overfilling at least one gas storage cylinder through a bleed line and a filling line from a suitable source of gas under pressure, while evacuating at least one other gas storage cylinder, and then simultaneously stopping the flow of gas to the overfilled cylinder through the filling line and connecting both the evacuated cylinder and the overfilled cylinder in com munication with such source of gas, by way of the filling line and such bleed line, so that the resulting rush of gas through the filling line to the evacuated cylinder reduces the pressure in the filling line to such an extent that excess gas bleeds from the over-filled cylinder back into the filling line, and closing the filled cylinder when the pressure of the gas in such filled cylinder drops to the desired value.

ANTON E. HI'ITL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Numher Name Date 1,786,858 Merrell et a1 Dec. 30, 1930 2,369,563 Gustin et a1 l Feb, 13, 1945 2,411,235 Smith Nov. 19, 1946 

